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Biomedical subjects

J B Kim

Publications and source records attributed to J B Kim.

126 records · Page 7Linked to original sources
PubMed1981

Development of a solid-phase chemiluminescence immunoassay for plasma progesterone.

A solid-phase immunoassay procedure for the determination of progesterone in human plasma is described, which utilizes chemiluminescence as the end-point. A progesterone-isoluminol conjugate serves as the chemiluminescent marker. An IgG fraction of antiserum to progesterone-11 alpha-hemisuccinate bovine serum albumin is passively adsorbed to the walls of Lumacuvettes P polystyrene test tubes. After the binding reaction, the cuvettes are washed. The light yield of the bound conjugate upon oxidation with a H2O2-microperoxidase system at pH 13 decreased with increasing free progesterone concentration in a log-linear manner over the range 15-1000 pg/tube. The chemiluminescence immunoassay is comparable to radioimmunoassay with regard to sensitivity, specificity, precision and accuracy. The assay offers the advantages of speed and ease of automation. In addition, this method does not involve the use of radioisotopes or of a centrifugation step.

Animals↗
PubMed1981

Use of monoclonal antibodies to pregnanediol-3 alpha-glucuronide for the development of a solid phase chemiluminescence immunoassay.

Monoclonal antibodies to pregnanediol-3 alpha-glucuronide were produced by hybridomas between P3-X63-Ag8 variants and spleen cell of mice immunized with a bovine serum albumin conjugate of the homologous hapten. The ascites fluid collected from mice inoculated with the cloned hybridoma cells contained antibodies with high specificity and affinity to pregnanediol-3 alpha-glucuronide. A sensitive solid-phase chemiluminescence immunoassay for urinary pregnanediol-3 alpha-glucuronide was established utilizing these antibodies. The assay was validated in terms of specificity, accuracy, sensitivity and precision. When urine samples were assayed for pregnanediol-3 alpha-glucuronide, the results obtained by the solid-phase chemiluminescence immunoassay method and the conventional gas liquid chromatographic method agreed well (n = 30, r = 0.96). The method may be of value for monitoring luteal function since it is fast, sensitive and does not require the use of radioisotopes or purification of the biological sample. Monoclonal antibody preparations facilitate rigorous standardization of the assay.

Animals↗
PubMed1980

An assay for urinary estriol-16 alpha-glucuronide based on antibody-enhanced chemiluminescence.

An immunoassay for estriol-16 alpha-glucuronide in pregnancy urine is described that utilizes antibody-enhanced chemiluminescence. The steroid glucuronide was covalently conjugated with the chemiluminescent marker aminobutyl-ethyl-isoluminol. The light yield of this conjugate upon oxidation was augmented by specific antibody, and this effect was inhibited by addition of the homologous steroid glucuronide (10-100 pg) in a dose-dependent manner. The assay does not require separation of bound and free ligand and proved satisfactory with respect to sensitivity, precision and accuracy. Assay results obtained by radioimmunoassay and chemiluminescence immunoassay were in good agreement (r = 0.98; n = 25).

Antibody Specificity↗
PubMed1980

An immunoassay for plasma cortisol based on chemiluminescence.

An immunoassay procedure for the determination of cortisol in human plasma is described, which utilizes chemiluminescence as the end point. A cortisol-isoluminol conjugate serves as the chemiluminescent marker. The light emission by this conjugate upon oxidation is delayed by prior incubation with anti-cortisol IgG, but not by unrelated gamma-globulin. This delayed light emission was inhibited by cortisol in a dose-dependent manner, with a linear range of 20-1000 pg steroid/assay tube. A competitive protein binding assay based on this procedure was applied to methylene chloride extracts of cortisol from normal and pathological human plasma (2-40 micrograms/100 ml). Cortisol values obtained by this procedure agreed well with those obtained by radioimmunoassay, using the same antiserum with tritiated cortisol as the label (r = 0.98). The chemiluminescence immunoassay is comparable to radioimmunoassay with regard to sensitivity, specificity, precision and accuracy. The advantage of the new assay procedure is that it obviates the need for counting radioactivity and for separation of bound and free ligand.

Humans↗
PubMedDate not supplied

Prophylactic effect of Korean mistletoe (Viscum album coloratum) extract on tumor metastasis is mediated by enhancement of NK cell activity.

We here demonstrated the prophylactic effect of an extract (KM-110) from Viscum album coloratum, a Korean mistletoe, on tumor metastasis produced by highly metastatic tumor cells, colon 26-M3.1 carcinoma, B16-BL6 melanoma and L5178Y-ML25 lymphoma cells, using experimental models in mice. Intravenous (i.v.) administration of KM-110 (100 microg/mouse) 2 days before tumor inoculation significantly inhibited lung metastasis of B16-BL6 and colon 26-M3.1 cells, and liver and spleen metastasis of L5178Y-ML25 cells. The prophylactic effect of KM-110 on tumor metastasis was evident with various administration routes, i.e. subcutaneous, oral, intranasal as well as i.v., and was dependent upon the dose of KM-110 administered. Furthermore, mice given KM-110 (100 microg) 2 days before tumor inoculation showed significantly prolonged survival rates compared with the untreated mice. In a time course analysis of NK activity, i.v. administration of KM-110 (100 microg) significantly augmented NK cytotoxicity to Yac-a tumor cells from 1 to 3 days after KM-110 treatment. Furthermore, depletion NK cells by injection of rabbit anti-asialo GM1 serum completely abolished the inhibitory effect of KM-110 on lung metastasis of colon 26-M3.1 cells. These results suggest that KM-110 possesses immunopotentiating activity which enhances the host defense system against tumors, and that its prophylactic effect on tumor metastasis is mediated by NK cell activation.

Animals↗
PubMedDate not supplied

PPAR gamma and the control of adipogenesis.

We recently cloned PPAR gamma as a factor that binds to an enhancer which has specificity for adipose cells. When expressed ectopically, PPAR gamma converts fibroblasts into bona fide preadipose cells. Upon application of activators or PPAR gamma ligands, these cells differentiate into fat cells. Most recently, we have been trying to understand the nature of natural ligands that activate PPAR gamma and the protein domains that control adipogenesis. With regards to ligands, we have shown that an unusual prostanoid, 15-deoxy delta 12,14PG J2, can bind to PPAR gamma and activate it. A second transcription factor that is induced early in differentiation, ADD1/SREBP1, appears to promote the formation of PPAR gamma ligands. Transfection of this molecule, a member of the bHLH family, causes the secretion of molecules that can serve as ligands for PPAR gamma. This ligand-like activity is specific for the gamma isoform of PPAR. Current studies are attempting to identify these potentially novel ligands. With regard to structure-function of PPAR gamma, we first analyzed the adipogenic activity of the three isoforms of PPAR: alpha, gamma and delta. Using appropriate activators of each it is clear that PPAR gamma has the most adipogenic action. PPAR alpha can be adipogenic with high levels of the strongest activators and PPAR delta does not stimulate fat cell differentiation. To identify the domain(s) of PPAR gamma responsible for differentiation, chimeras between PPAR gamma and PPAR delta were created and transfected into fibroblasts. This has allowed the isolation of relatively small regions of this molecule that are responsible for differentiation.

Adipocytes↗